AB0564 PROGNOSTIC ROLE OF PRE-CONCEPTIONAL COMPLEMENT CONSUMPTION ON PREGNANCY OUTCOMES IN ANTI-PHOSPHOLIPID ANTIBODY SYNDROME, POLIABORTIVITY AND RECURRENT IMPLANTATION FAILURE
Authors: V. Canti, R. De Lorenzo, C. Gerbino, G. Adorno, F. Pasi, M. T. Castiglioni, P. Rovere-Querini
Journal: Annals of the Rheumatic Diseases (2022)

Background In anti-phospholipid antibody syndrome (APS), complement (C3/C4) activation favours the development of adverse pregnancy events. The prognostic role of complement in recurrent pregnancy loss (RPL) and recurrent implantation failure (RIF) has never been clinically studied. Additionally, the influence of hydroxychloroquine and heparin on complement modulation at the molecular level has already been accepted, while few clinical studies on these drugs have been published up to date. Objectives The aim of the study was to investigate whether C3/C4 levels represent a risk factor for pregnancy outcomes in a population of patients with APS, patients with RPL and patients with RIF. Moreover, the study investigated the effects of therapies during pregnancy (low dose aspirin, low molecular weight heparin and hydroxychloroquine and their combinations). Methods We collected data of 136 patients (33 APS, 69 RPL, 34 RIF) prospectively followed from September 2018 to June 2021 in the “Recurrent pregnancy loss and Recurrent implantation failure clinic” of the “Centro Scienze della Natalità” department of San Raffaele Hospital, Milan, Italy. For all the patients, serum C3/C4 levels were determined at San Raffaele local laboratory. Results 30/136 (22%) patients had pre-conceptional complement consumption. Of these, 5/30 (17%) had anamnestic history of adverse pregnancy outcomes and 29/30 (97%) had at least one abortion in the past. 106/136 (78%) patients had normal pre-conceptional complement levels: 8/106 (7%) had anamnestic history of adverse pregnancy outcomes and 91/106 (86%) had at least one abortion in the past. In 64/136 pregnancies prospectively followed in our centre, 17/64 (26%) had pre-conceptional complement consumption. In patients with complement consumption, abortion (4/17, 24%) and adverse pregnancy outcomes (3/17, 18%) rates were homogeneous to the ones of patients with normal complement levels (16/47, 34% e 5/47, 11% respectively). Hypocomplementemia was associated with a significantly higher (p&lt;0.05) probability of active treatment during pregnancy (both with low dose aspirin, low molecular weight heparin and hydroxychloroquine), which might explain the uniformity of gestational outcomes between the two groups. Thus, additional therapy with hydroxychloroquine provided in our clinic might have improved gestational outcomes in patients with hypocomplementemia. Conclusion Measurement of pre-conceptional complement level is an easy and cheap procedure that might be useful to identify those patients at a higher risk of adverse gestational outcomes. The presence of consumed pre-conceptional C3/C4 levels might represent an indication to strengthen therapy in those pregnant patients with history of pregnancy loss. Our study stresses the importance of a personalized diagnostic-therapeutic pathway in patients with RPL and RIF, independently of the presence of APS. Further studies in larger cohorts with RPL and RIF will be needed to confirm our findings. Disclosure of Interests None declared